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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* lang属性给到span 但是通过em添加伪类选择器，依然可以选择到对应的元素 */
    em:lang(zh) {
      font-weight: 700;
      /* 强调符号 */
      text-emphasis: dot;
    }
    em:lang(en) {
      color: red;
    }
  </style>
</head>
<body>
  <span lang="zh">
    这是
    <em>重点</em>
    <em>importance</em>
  </span>
</body>
</html>